NATO has held its first war games focused on defending a land corridor along the Polish-Lithuanian border sandwiched between Russia's Kaliningrad exclave and Kremlin's close ally, Belarus.

Lithuanian President Dalia Grybauskaite said on June 19 that the drills sent a "strong message of NATO readiness and commitment to ensure security of the region."

More than 1,500 troops from the United States, Poland, Britain, Lithuania, and Croatia took part in the exercises on June 17-18.

Fears that Russia could attempt an attack on the Suwalki Gap land corridor surged after Moscow's 2014 illegal annexation of Crimea from Ukraine, a move that sent East-West relations to their lowest point since the Cold War.

The drills were held days after Russia, Belarus, and Serbia held joint military exercises near the Belarusian border with Poland.